Air sampling system



Nov. 13, 1962 w. F. HUCH ETAL 3,063,296

AIR SAMPLING SYSTEM Filed April 30, 1959 3 Sheets-Sheet 1 INVENTORS WILLIAM E HUCH EDWARD P. NEY

Nov. 13, 1962 w. F. HUCH ETAL AIR SAMPLING SYSTEM 3 SheetsSheet 2 Filed April 30, 1959 INVENTORS WILLIAM F- HUCH EDWARD P. NEY

Nov. 13, 1962 w. F. HUCH ETAL 3,063,296

AIR SAMPLING SYSTEM Filed April 30, 1959 3 Sheets-Sheet 3 INVENTOR. WILLIAM F. How By EDWARD R NEY United 3,063,296 AIR SAMPLING SYSTEM William F. Huch, St. Paul, and Edward P. Ney, Minneapolis, Minn., assignors, by mesne assignments, to the United States of America as represented by the ecretary of the Navy 7 Filed Apr. 30, 1959, Sen No. 810,206 9 Claims. (Cl. 73421.5)

This invention relates to the collection of high altitude air samples, and is concerned more particularly with improved means for and methods of obtaining air samples.

It is frequently desirable to ascertain various facts concerning high altitude air, and it is accordingly an object of the invention to provide apparatus which may be carried aloft and at a predetermined high altitude collect a large sample of uncontaminated atmospheric air, .and return the sample to earth.

A further object is to provide a container which automatically opens at a predetermined high altitude, selfinflates with an atmospheric air sample, and automatically closes after inflation.

A still further object of the invention is to carry aloft a deflated bag, subpressure it at a predetermined altitude, open the bag, close it when it is filled with a sample of atmospheric air at that altitude, and deliver the inflated bag to earth.

Another object is to provide improved methods of obtaining atmospheric air samples.

A further object is to provide simple methods of obtaining uncontaminated air samples.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection With the accompanying more or less schematic drawings, wherein:

FIG. 1 is an elevational view of an air sample collection balloon system as it appears at or near ceiling altitude, with the collector bag collapsed and'limp.

FIG. 2 is an enlarged perspective view of the bag and associated structure of FIG. 1.

FIG. 3 is an enlarged view, partly in section, of the 1 bag valve and other control mechanism, showing the valve open.

FIG. 4 is a wiring diagram for the control mechanism.

FIG. 5 is similar to FlG. 3 but shows the valve closed and the arrangement of the clock mechanism at launching" of the system.

FIGS. 6 and 7 show the collector bag and associated structure at ceiling altitude just as the frame and bag have shifted to invert the bag and subject it to internal sub-pressure, the bag valve being about to open or havin'g'jiist opened.

FIG. 8 issimilar to FIGS. 6 and 7 but shows the bag fully'inflated, and the frame still attached.

FIGS. 9 and 10 are similar to FIG. 8 but show the inflated closed bag before and after the frame has been jettisoned and the parachute released from the balloon.

Referring now more particularly to the drawings, disclosing an illustrative embodiment of the invention, there is shown in" FIG. 1 a'towing vehicle in the form of a balloon 12 from which hangs a load line 14 passing through a line Cutter 1.6 and connected to a parachute 18 having a load line 21'} supporting .a collapsed air sample collector bag 22' Whose area'is divisible into four essentially equilateral triangles so that it is capable of being inflated to a degree such that it assumes the shape substantially of' a regular tetrahedron. When fully infiated, such a bag is of course billowed out and rounded throughout except at its corners. As also shown in FIG. 2, three' corners 2,4 of the bag 22 are connected to the 3,663,296 Patented Nov. 13, 1962 lines 26, 28 and 36 of a harness 32 connected to the parachute line 211; when the harness lines are fully eX- tended in flight they hold the corners 24 substantially horizontally coplanar. The corners 24 are also connected by lines 34 of equal length passing through cutters 36 to the corners 38,411, and 42, respectively, of an equilateral triangular frame 44, of aluminum or other suitable material, whose corner 38 is connected by a line 46 passing through a cutter 48 to the parachute line 20, the line 46 being of such length that the frame is nearly vertical, the harness line 26 is slack, and the harness lines 23 and 36 are under tension. The several cutters are preferably of the electrically fired squib type.

The regular tetrahedron is slightly incomplete to the extent that its fourth corner is slightly truncated to provide an opening 52 (FIG. 3) defined by a rim 5'4 clamped, as by a circumferential series of bolts 56, between a clamp ring 513 and a plate 60 having an opening 62 communicating with the bag opening 52. At the bottom of the plate 66 adjacent its opening 62 is an O ring or other suitable means serving as a seat 64 forming part of a valve 66 including a valve plunger 68 whose stern 76 extends through bearings 72 and 74 carried by a bracket 76 supported by the plate. A spring 73 about the stem 76 and between the bearing 74 and a stem flange 86 biases the plunger 68 in the direction to close the valve 66.

An electric clock 84 (FIG. 4) supported by the plate 66 includes a rotor disc 86 (FIGS. 3 and 5) turning, say, once in four hours. The disc 86 has a lug or crank 88 for engaging the flange 86 to open the valve 66. A microswitch 96 supported by the plate 66 has a contact 92 connected to the squib of the cutter 16, a contact 94 connected to the motor of the clock 84, and a switch plunger or arm 96 spring-biased toward the cutter contact. A battery 98, a hand switch 106, and wiring cooperate with the cutter 16, clock 84 and switch 96 to connect the cutter and clock in parallel (FIG. 4). The disc 86 has a circular peripheral surface 102 which, when engaged with the switch arm 96, holds the arm against the clock contact 94. The surface 162 is interrupted by a notch 104 into which the arm 96 is adapted to snap to open the clock circuit and close the cutter circuit. The notch 164 has an abrupt trailing wall 106 operative as a detent to engage .a side of the arm 96 to prevent the arm from re-engagement with the surface 102 and thus to prevent re-closing of the clock circuit.

A second microswitch 110 carried by the plate 66 comprises a switch arm or plunger 112 selectively occupying a null position (FIG. 4) or engaging a contact 114 in series with the cutter 48 or a contact 116 between which and the battery 98 the cutters 36are arranged in parallel. The clock 64 is provided with a second rotor disc 118 which cooperates with the switch arm 112. To this end, the disc 118 has two circular peripheral surfaces 120 and 122 of the same radius and alternating with a cam node 124 .and a notch 126 having a gently sloping trailing cam Wall 128. While the switch arm 112 rides on the surface 120 or the surface 122, the arm 112 is in its null position. When the arm 112 is cammed by the node 124, the arm engages the contact 114 to fire the cutter 48; on snapping into the notch 126, the arm engages the contact 116 with the result that the cutters 36 are fired.

A perforated protective dome 130 secured circum ferentially as at 132 to the plate 60 forms withthe plate a housing 134 for the clock, valve, battery and switches.

In preparation for launching of the system, the valve 66 is held open against the bias of the spring 78 and the bag 22 is evacuated in any suitable manner and then the spring is allowed to close the valve. The balloon 12 is inflated with lift gas until it has suflicient lift to carry the system to a predetermined ceiling altitude, at which a sample of the ambient atmospheric air is to be obtained, in a predetermined period which we will here assume to be within a few minutes or so short of 3% hours after launching. All other launching preparations having been completed, the hand switch 109 is closed, thereby starting the clock 84, and the system is launched. The arrangement of the various parts of the mechanism at launching is as shown in FIG. 5. When the system reaches ceiling altitude, the node 124 cams the switch arm 112 into engagement with the contact 114, firing the cutter 48 which severs the line 46, thereby releasing the upper corner 38 (FIGS. 1 and 2) of the frame 44 from the parachute line 20, so that the corner swings down until the slack is taken out of the harness line 26, whereupon the frame and the plane of the bag corners 24 are horizontal (FIGS. 6 and 7), with the bag inverted.

Now the collapsed bag 22 is supported solely by the harness lines 26, 28, and 30, and is weighed down at its corners 24 by the frame 44 and at its bottom or apex by the housing 134 and associated mechanism, with the result that the bag is puckered, with the center of its inverted base near the volumetric center of the bag, and the centers of the remaining triangular areas of the bag also near the volumetric center of the bag. Accordingly the entire bag film is under tension tending to impart a tetrahedral shape to the bag and thus sub-pressuring the interior i.e., tending to increase the volume, of the bag, so that the interior is at lower pressure than the ambient atmosphere.

When the interior of the bag 22 is brought to the con: dition of sub-pressure, let it be assumed that 3% hours have elapsed since launching. At this point the crank 88 is timed to encounter the flange 8t) and open the valve 66, whereupon the bag proceeds to self-inflate. The bag 22 may be designed to become fully inflated in, say, /2 hour, and accordingly the valve 66 may be held open for that period, at the end of which the crank 88 is timed to clear the flange 30, allowing the spring 78 to snap the valve shut.

FIGS. 8, 9, and show the bag 22 fully inflated. Promptly after the valve 66 closes the inflated bag 22, the switch arm 112 enters the notch 126 and thus engages the contact 116, firing the cutters 36 so that the lines 34 are severed and the frame 44 is jettisoned (FIGS. 9 and 10) without injuring the bag. Promptly thereafter or coincidentally therewith, the arm 96 enters the notch 104, disengages the contact 94, thereby stopping the clock 84, engages the contact 92, thereby firing the blow-down cutter 16 and thereby severing the balloon load line 14, whereupon the parachute opens and floats the inflated bag 22 and associated mechanism to earth, and the arm 96 abuts the detent shoulder 106 so that the arm cannot climb out of the notch and hence cannot restart the clock.

If desired, the line 46 could be omitted, so that the frame and the plane of the apices 24 will be horizontal from the inception of the launching. However, it is advisable to use the line 46 as explained above for the reason that, if there is a small leak in the bag, the bag will not fill with air at an altitude below ceiling altitude, inasmuch as, with the frame held substantially vertical by the line 46, the bag is not subpressured, but is limp at atmospheric pressure.

The balloon 12 and bag 22 may be made of any suitable material, preferably inelastic film which is light in weight yet will withstand the low temperatures at high altitudes. Examples of such film are polyethylene and Mylar.

When it is desired to investigate the helium balance in the stratosphere or other high altitude, the balloon lift gas should not be helium, since this gas diffuses through the balloon film and may also leak therefrom, and thus contaminate the sample. The atmosphere would also be contaminated by balloon helium escaping through any appendix or valve with which the balloon might be 4 equipped. To preclude such contamination, the balloon lift gas used is hydrogen.

Although the collector bag is shown as being of the regular tetrahedral type, it could be of any right pyramidal type, that is, one whose base is a regular polygon, whether an equilateral triangle as shown, or a square, pentagon or other, and whose altitude extends to the center of the base, and the shape of the frame and the number of harness lines and lines connecting the frame to the bag base corners be made to correspond. The regular tetrahcdron is preferred, however, since it affords a maximum volume-to-weight ratio and thus is most economical in bag material, frame construction, and number of lines and cutters.

The balloon may be of any suitable type capable of remaining at ceiling altitude. It may therefore be of the sealed type which at ceiling altitude is super-pressured, or it may be of the valved type.

Obviously many modifications and variations of the invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

We claim:

1. Apparatus for obtaining a sample of high altitude atmospheric air, comprising a balloon having a predetermined ceiling altitude at which the sample is to be obtained, a load line suspended from the balloon, a parachute suspended from the load line, an evacuated collapsed bag capable, when partially inflated, of assuming substantially the shape of a right pyramid, a harness comprising lines connecting the bottom of the parachute to the corners of the pyramid base and, when extended, holding the corners in a horizontal plane, a regular polygonal frame larger than and similar in shape to the outline of the base, lines connecting the corners of the frame to the respective corners of the base, a line suspending the frame substantially vertically from the parachute, the apex of the bag having an opening, mechanism carried by the bag at the apex and including a valve, and a spring holding the valve in a position in which the valve closes the opening, means controlled by the mechanism for severing the frame-suspending line when the balloon reaches ceiling altitude, whereupon the harness lines are extended and the frame is supported solely by the base corners, and the interior of the bag is sub-pressured by the frame and the weight of the mechanism, the mechanism including means, operative when the interior of the bag is sub-pressured, to open the valve and maintain it open only until sufiicient ambient atmospheric air is sucked into the bag to inflate it to substantially the pressure of the ambient atmospheric air, whereupon the valve is sprung to closed position, and means controlled by the mechanism for severing the load line and the corner-connecting lines on closing of the valve after inflation of the bag.

2. Apparatus for obtaining a sample of high altitude atmospheric air, comprising a balloon having a load line and adapted to reach ceiling altitude in a predetermined period of time after launching, a parachute suspended from the load line, an equilateral triangular frame, a line suspending the frame substantially vertically from the parachute, a collapsed bag capable of being inflated to the shape substantially of a tetrahedron having an equilateral base smaller than the interior of the frame, a set of lines connecting the corners of the base of the collapsed bag to the respective corners of the frame, the apex having an opening, mechanism carried by the bag at the apex and including a valve for the opening, a spring closing the valve, and a timer, means controlled by the timer for cutting the frame-suspending line when the balloon reaches ceiling altitude, and harness lines connecting the base corners to the parachute and supporting the base corners in a horizontal plane when the frame suspending line is cut, the frame then cooperating with the weight of the mechanism to sub-pressure the interior of the bag, the mechanism including means timed to open the valve when the base assumes a horizontal position, enabling the bag to self-inflate, and to enable the spring to close the valve when the bag is at least partially inflated, and means controlled by the timer for cutting the load line and the corner-connecting lines when the valve is closed after inflation of the bag.

3. In an apparatus for obtaining a sample of high altitude air, a closed collapsed deflated bag adapted when inflated to assume substantially the shape of a right pyramid, means suspending the bag inverted with the corners of its base in a horizontal plane, means connected to the corners of the base and to the apex and exerting tension on the bag in directions to sub-pressure the interior of the bag, means for opening the bag to enable the bag to self-inflate, and means for closing the inflated bag.

4. In an apparatus for obtaining a sample of high altitude atmospheric air, a closed collapsed bag capable on inflation of assuming the shape of a regular tetrahedron, means exerting pull on the several corners of the closed bag in directions to subject substantially the entire area of the bag to tension and thereby sub-pressure the interior of the bag, means for opening the sub-pressured bag to high altitude atmosphere to enable the bag to selfinflate, and means for closing the inflated bag.

5. In an apparatus for obtaining a sample of high altitude atmospheric air, a balloon, a closed collapsed bag having at least three corners defining a base and having an apex and capable of assuming the shape of a right pyramid when inflated, means including a harness connecting the respective corners to the balloon, with the corners in a horizontal plane and the apex lowermost, a regular polygonal frame having the same number of corners as the base of the bag, the interior of the frame being larger than the base of the pyramid, lines of equal length connecting the respective corners of the frame to corresponding corners of the bag and maintaining the frame and the base of the bag substantially coplanar, the bag having an opening at its apex, mechanism carried by the bag adjacent the opening and including a valve closing the opening, the frame and the weight of the mechanism cooperating in tensioning the entire area of the bag and thereby sub-pressuring the interior of the bag, the mechanism including means for opening the valve to enable the bag to self-inflate and means for closing the valve when the bag is inflated.

6. The structure of claim 5, together with means for jettisoning the frame when the bag is inflated.

7. The structure of claim 5, together with a parachute connected between the balloon and the harness, and means for freeing the balloon from the parachute and jettisoning the frame when the bag is inflated.

8. In an apparatus for obtaining a sample of uncontaminated high altitude atmospheric air for investigating the helium balance of such air, a balloon inflated with lift gas devoid of helium and adapted to reach and remain at a ceiling altitude at which the sample is to be obtained, a closed collapsed inelastic film bag capable when inflated of assuming the shape of a right pyramid, means suspending the bag from the balloon, with the corners of the base of the bag in substantially the same plane, means connected to the bag and subjecting the base to uniform substantially radial tension along lines passing through the corners, means connected to the bag and subjecting the remainder of the area of the bag to uniform tension, whereby the interior of the bag is subpressured, means for opening the bag at ceiling altitude to allow it to self-inflate, and means for closing the inflated bag at ceiling altitude.

9. In a method of obtaining a sample of high altitude air, the steps of collapsing and closing a bag on the ground, supporting the bag so that it is limp, carrying the limp bag to the desired altitude, subjecting the interior of the bag while at that altitude to sub-pressure while the bag is closed, opening the bag to the high altitude air to enable the bag to self-inflate, closing the inflated bag, and removing the sub-pressuring influence from the inflated bag.

References Cited in the file of this patent UNITED STATES PATENTS 2,223,785 Hassler Dec. 3, 1940 2,374,227 Metcalf Apr. 24, 1945 2,468,021 Black Apr. 26, 1949 2,645,940 Kohl et a1. July 21, 1953 2,906,125 JeWett Sept. 29, 1959 2,943,490 Melton July 5, 1960 

